Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.stream.IntStream;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.OptionalInt;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Pradyumn Agrawal coderbond007
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastReader in = new FastReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, FastReader in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();
            int[][] matrix = in.nextIntMap(n, m);
            int[][] tempMatrix = new int[n][m];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < m; j++) {
                    tempMatrix[i][j] = matrix[i][j];
                }
            }
            String[] ans1 = solveColFirst(matrix);
            String[] ans2 = solveRowFirst(tempMatrix);
            if (ans1[0].equals("-1")) {
                out.println(-1);
            } else {
                int moves1 = Integer.parseInt(ans1[0]);
                int moves2 = Integer.parseInt(ans2[0]);
                if (moves1 < moves2) {
                    out.println(moves1);
                    out.println(ans1[1]);
                } else {
                    out.println(moves2);
                    out.println(ans2[1]);
                }
            }
        }

        public String[] solveColFirst(int[][] matrix) {
            int n = matrix.length;
            int m = matrix[0].length;
            int moves = 0;
            StringBuilder stringBuilder = new StringBuilder();
            for (int j = 0; j < m; j++) {
                int minValue = minOfCol(matrix, j, n);
                if (minValue > 0) {
                    moves += minValue;
                    for (int i = 1; i <= minValue; i++) {
                        stringBuilder.append("col ");
                        stringBuilder.append(j + 1);
                        stringBuilder.append("\n");
                    }
                    for (int i = 0; i < n; i++) {
                        matrix[i][j] -= minValue;
                    }
                }
            }
            for (int i = 0; i < n; i++) {
                int minValue = Arrays.stream(matrix[i]).min().getAsInt();
                if (minValue > 0) {
                    moves += minValue;
                    for (int j = 1; j <= minValue; j++) {
                        stringBuilder.append("row ");
                        stringBuilder.append(i + 1);
                        stringBuilder.append("\n");
                    }
                    for (int j = 0; j < m; j++) {
                        matrix[i][j] -= minValue;
                    }
                }
            }
            String[] ans = new String[2];

            if (check(matrix)) {
                return new String[]{Integer.toString(moves), stringBuilder.toString()};
            } else {
                return new String[]{Integer.toString(-1), Integer.toString(-1)};
            }
        }

        public String[] solveRowFirst(int[][] matrix) {
            int n = matrix.length;
            int m = matrix[0].length;
            int moves = 0;
            StringBuilder stringBuilder = new StringBuilder();
            for (int i = 0; i < n; i++) {
                int minValue = Arrays.stream(matrix[i]).min().getAsInt();
                if (minValue > 0) {
                    moves += minValue;
                    for (int j = 1; j <= minValue; j++) {
                        stringBuilder.append("row ");
                        stringBuilder.append(i + 1);
                        stringBuilder.append("\n");
                    }
                    for (int j = 0; j < m; j++) {
                        matrix[i][j] -= minValue;
                    }
                }
            }
            for (int j = 0; j < m; j++) {
                int minValue = minOfCol(matrix, j, n);
                if (minValue > 0) {
                    moves += minValue;
                    for (int i = 1; i <= minValue; i++) {
                        stringBuilder.append("col ");
                        stringBuilder.append(j + 1);
                        stringBuilder.append("\n");
                    }
                    for (int i = 0; i < n; i++) {
                        matrix[i][j] -= minValue;
                    }
                }
            }

            if (check(matrix)) {
                return new String[]{Integer.toString(moves), stringBuilder.toString()};
            } else {
                return new String[]{Integer.toString(-1), Integer.toString(-1)};
            }
        }

        public boolean check(int[][] matrix) {
            boolean zero = true;
            for (int[] row : matrix) {
                for (int val : row) {
                    zero &= val == 0;
                }
            }
            return zero;
        }

        public static int minOfCol(int[][] matrix, int col, int n) {
            int min = Integer.MAX_VALUE;
            for (int i = 0; i < n; i++) {
                min = Math.min(min, matrix[i][col]);
            }
            return min;
        }

    }

    static class FastReader {
        private InputStream stream;
        private byte[] buf = new byte[8192];
        private int curChar;
        private int pnumChars;
        private FastReader.SpaceCharFilter filter;

        public FastReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if (pnumChars == -1) {
                throw new InputMismatchException();
            }
            if (curChar >= pnumChars) {
                curChar = 0;
                try {
                    pnumChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (pnumChars <= 0) {
                    return -1;
                }
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if (c == ',') {
                    c = read();
                }
                if (c < '0' || c > '9') {
                    throw new InputMismatchException();
                }
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int[] nextIntArray(int n) {
            int[] array = new int[n];
            for (int i = 0; i < n; i++) {
                array[i] = nextInt();
            }
            return array;
        }

        public int[][] nextIntMap(int n, int m) {
            int[][] array = new int[n][];
            for (int i = 0; i < n; i++) {
                array[i] = nextIntArray(m);
            }
            return array;
        }

        public boolean isSpaceChar(int c) {
            if (filter != null) {
                return filter.isSpaceChar(c);
            }
            return isWhitespace(c);
        }

        public static boolean isWhitespace(int c) {
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);

        }

    }
}